Abstract: A video camera captures images of retroreflection from the retina of an eye. These images are captured while the eye rotates. Thus, different images are captured in different rotational positions of the eye. A computer calculates, for each image, the eye's direction of gaze. In turn, the direction of gaze is used to calculate the precise location of a small region of the retina at which the retroflection occurs. A computer calculates a digital image of a portion of the retina by summing data from multiple retroreflection images. The digital image of the retina may be used for many practical applications, including medical diagnosis and biometric identification. In some scenarios, the video camera captures detailed images of the retina of a subject, while the subject is so far away that the rest of the subject's face is below the diffraction limit of the camera.

Abstract: In illustrative implementations of this invention, light sources illuminate a surface with multi-spectral, multi-directional illumination that varies in direction, wavelength, coherence and collimation. One or more cameras capture images of the surface while the surface is illuminated under different lighting conditions. One or more computers take, as input, data indicative of or derived from the images, and determine a classification of the surface. Based on the computed classification, the computers output signals to control an I/O device, such that content displayed by the I/O device depends, at least in part, on the computed classification. In illustrative implementations, this invention accurately classifies a wide range of surfaces, including transparent surfaces, specular surfaces, and surfaces with few features.

Abstract: A retinal imaging device includes a camera, a light source, a projector, an I/O device and a computer. The projector emits two sets of light rays, such that one set of rays lies on an exterior surface of a first cone, and the other set of rays lie on an exterior surface of a second cone. The user adjusts the position of his or her eye relative to the camera, until the rays form a full, undistorted target image on the retina. This full, undistorted image is only seen when the pupil of the eye is positioned in the intersection of the first and second cones, and the eye is thus aligned with the camera. The user provides input, via the I/O device, that the user is seeing this image. The computer then instructs the camera to capture retinal images and the light source to simultaneously illuminate the retina.

Abstract: In illustrative implementations of this invention, an imaging system includes multiple light sources that illuminate a scene, and also includes a lock-in time of flight camera. While the scene is illuminated by these light sources, each of the light sources is amplitude-modulated by a different modulation pattern, and a reference signal is applied to the lock-in time-of-flight camera. The modulation patterns and the reference signal are carefully chosen such that the imaging system is able to disentangle, in real time, the respective contributions of the different light sources, and to compute, in real-time, depth of the scene. In some cases, the modulation signals for the light sources are orthogonal to each other and the reference signal is broadband. In some cases, the modulation codes for the light sources and the reference code are optimal codes that are determined by an optimization algorithm.

Abstract: An active imaging system, which includes a light source and light sensor, generates structured illumination. The light sensor captures transient light response data regarding reflections of light emitted by the light source. The transient light response data is wavelength-resolved. One or more processors process the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of an occluded surface. The processors also compute a 3D geometry of the occluded surface.

Abstract: In exemplary implementations of this invention, a camera can capture multiple millions of frames per second, such that each frame is 2D image, rather than a streak. A light source in the camera emits ultrashort pulses of light to illuminate a scene. Scattered light from the scene returns to the camera. This incoming light strikes a photocathode, which emits electrons, which are detected by a set of phosphor blocks, which emit light, which is detected by a light sensor. Voltage is applied to plates to create an electric field that deflects the electrons. The voltage varies in a temporal “stepladder” pattern, deflecting the electrons by different amounts, such that the electrons hit different phosphor blocks at different times during the sequence. Each phosphor block (together with the light sensor) captures a separate frame in the sequence. A mask may be used to increase resolution.

Abstract: A 3D imaging system uses a depth sensor to produce a coarse depth map, and then uses the coarse depth map as a constraint in order to correct ambiguous surface normals computed from polarization cues. The imaging system outputs an enhanced depth map that has a greater depth resolution than the coarse depth map. The enhanced depth map is also much more accurate than could be obtained from the depth sensor alone. In many cases, the imaging system extracts the polarization cues from three polarized images. Thus, in many implementations, the system takes only three extra images—in addition to data used to generate the coarse depth map—in order to dramatically enhance the coarse depth map.

Abstract: In exemplary implementations of this invention, light from a light field projector is transmitted through an angle-expanding screen to create a glasses-free, 3D display. The display can be horizontal-only parallax or full parallax. In the former case, a vertical diffuser may positioned in the optical stack. The angle-expanding screen may comprise two planar arrays of optical elements (e.g., lenslets or lenticules) separated from each other by the sum of their focal distances. Alternatively, a light field projector may project light rays through a focusing lens onto a diffuse, transmissive screen. In this alternative approach, the light field projector may comprise two spatial light modulators (SLMs). A focused image of the first SLM, and a slightly blurred image of the second SLM, are optically combined on the diffuser, creating a combined image that has a higher spatial resolution and a higher dynamic range than either of two SLMs.

Abstract: In exemplary implementations of this invention, a multi-frequency ToF camera mitigates the effect of multi-path interference (MPI), and can calculate an accurate depth map despite MPI. A light source in the multi-frequency camera emits light in a temporal sequence of different frequencies. For example, the light source can emit a sequence of ten equidistant frequencies f=10 MHz, 20 MHz, 30 MHz, . . . , 100 MHz. At each frequency, a lock-in sensor within the ToF camera captures 4 frames. From these 4 frames, one or more processors compute, for each pixel in the sensor, a single complex number. The processors stack all of such complex quantities (one such complex number per pixel per frequency) and solve for the depth and intensity, using a spectral estimation technique.

Abstract: In an example embodiment, a method, apparatus and computer program product are provided. The method includes facilitating capture of at least one image of a scene including a foreground object by at least one rolling shutter sensor. The at least one image includes a pattern in an image region of the foreground object comprising a series of alternate dark and bright pixel regions. The at least one image is captured by setting exposure time of the sensor as equal or less than a read-out time of a set of pixel rows of a plurality of pixel rows, and by facilitating a repeating sequence of ON and OFF of flash such that flash is ON while capturing the set of pixel rows, and OFF while capturing subsequent set of pixel rows. The method includes determining a contour of the foreground object in the at least one image based on the pattern.

Abstract: A projector and one or more optical components project a light pattern that scans at least a portion of an anterior segment of an eye of a user, while one or more cameras capture images of the anterior segment. During each scan, different pixels in the projector emit light at different times, causing the light pattern to repeatedly change orientation relative to the eye and thus to illuminate multiple different cross-sections of the anterior segment. The cameras capture images of each cross-section from a total of at least two different vantage points relative to the head of the user. The position of the projector, optical components and cameras relative to the head of the user remains substantially constant throughout each entire scan.

Abstract: In exemplary implementations of this invention, a depth-sensing system includes multiple light sources, multiple cameras, a pattern generator and one or more computers. The system measures depth in a scene. The multiple light sources emit light that illuminates a pattern generator. The pattern generator refracts, reflects or selectively attenuates the light, to create a textured light pattern that is projected onto the scene. The multiple cameras capture images of the scene from different viewpoints, while the scene is illuminated by the textured light. One or more computers process the images and compute the depth of points in the scene, by a computation that involves stereoscopic triangulation.

Abstract: In exemplary implementations of this invention, a light field camera uses a light field dictionary to reconstruct a 4D light field from a single photograph. The light field includes both angular and spatial information and has a spatial resolution equal to the spatial resolution of the imaging sensor. Light from a scene passes through a coded spatial light modulator (SLM) before reaching an imaging sensor. Computer processors reconstruct a light field. This reconstruction includes computing a sparse or compressible coefficient vector using a light field dictionary matrix. Each column vector of the dictionary matrix is a light field atom. These light field atoms each, respectively, comprise information about a small 4D region of a light field. Reconstruction quality may be improved by using an SLM that is as orthogonal as possible to the dictionary.

Abstract: In exemplary implementations of this invention, a bi-ocular apparatus presents visual stimuli to one eye of a human subject in order to relax that eye, while measuring refractive aberration of the subject's other eye. Alternately, a monocular device presents stimuli to relax an eye while testing the same eye. The apparatus induces eye relaxation by displaying virtual objects at varying apparent distances from the subject. For example, the apparatus may do so by (i) changing distance between a backlit film and a lens; (ii) using extra lenses; (iii) using an adaptive lens that changes power; (v) selecting distinct positions in a progressive or multi-focal length lens; (vi) selecting distinct optical depths by fiber optical illumination; (vii) displaying a 3D virtual image at any given apparent depth; or (viii) display both a warped version of the real world and a test image at the same time.

Abstract: An active imaging system, which includes a light source and light sensor, generates structured illumination. The light sensor captures transient light response data regarding reflections of light emitted by the light source. The transient light response data is wavelength-resolved. One or more processors process the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of an occluded surface. The processors also compute a 3D geometry of the occluded surface.

Abstract: In exemplary implementations of this invention, light from a backlight is transmitted through two stacked LCDs and then through a diffuser. The front side of the diffuser displays a time-varying sequence of 2D images. Processors execute an optimization algorithm to compute optimal pixel states in the first and second LCDs, respectively, such that for each respective image in the sequence, the optimal pixel states minimize, subject to one or more constraints, a difference between a target image and the respective image. The processors output signals to control actual pixel states in the LCDs, based on the computed optimal pixel states. The 2D images displayed by the diffuser have a higher spatial resolution than the native spatial resolution of the LCDs. Alternatively, the diffuser may be switched off, and the device may display either (a) 2D images with a higher dynamic range than the LCDs, or (b) an automultiscopic display.

Abstract: In exemplary implementations of this invention, two LCD screens display a multi-view 3D image that has both horizontal and vertical parallax, and that does not require a viewer to wear any special glasses. Each pixel in the LCDs can take on any value: the pixel can be opaque, transparent, or any shade between. For regions of the image that are adjacent to a step function (e.g., a depth discontinuity) and not adjacent to a sharp corner, the screens display local parallax barriers comprising many small slits. The barriers and the slits tend to be oriented perpendicular to the local angular gradient of the target light field. In some implementations, the display is optimized to seek to minimize the Euclidian distance between the desired light field and the actual light field that is produced. Weighted, non-negative matrix factorization (NMF) is used for this optimization.

Abstract: In exemplary implementations, this invention comprises apparatus for retinal self-imaging. Visual stimuli help the user self-align his eye with a camera. Bi-ocular coupling induces the test eye to rotate into different positions. As the test eye rotates, a video is captured of different areas of the retina. Computational photography methods process this video into a mosaiced image of a large area of the retina. An LED is pressed against the skin near the eye, to provide indirect, diffuse illumination of the retina. The camera has a wide field of view, and can image part of the retina even when the eye is off-axis (when the eye's pupillary axis and camera's optical axis are not aligned). Alternately, the retina is illuminated directly through the pupil, and different parts of a large lens are used to image different parts of the retina. Alternately, a plenoptic camera is used for retinal imaging.

Abstract: In exemplary implementations of this invention, an aberrometer is used to measure the refractive condition of any eye. An artificial light source emits light that travels to a light sensor. Along the way, the light enters and then exits the eye, passes through or is reflected from one or more spatial light modulators (SLMs), and passes through an objective lens-system. The SLMs modify a bokeh effect of the imaging system (which is only visible when the system is out-of-focus), creating a blurred version of the SLM patterns. The light sensor then captures one or more out-of-focus images. If there are refractive aberrations in the eye, these aberrations cause the SLM patterns captured in the images to be distorted. By analyzing differences between the distorted captured patterns and the undistorted SLM patterns, refractive aberrations of the eye can be computed and an eyewear measurement generated.

Abstract: An active imaging system, which includes a light source and light sensor, generates structured illumination. The light sensor captures transient light response data regarding reflections of light emitted by the light source. The transient light response data is wavelength-resolved. One or more processors process the transient light response data and data regarding the structured illumination to calculate a reflectance spectra map of an occluded surface. The processors also compute a 3D geometry of the occluded surface.